Apparatus for the production of pipe



Aug. 3, 1954 J. A. HJULIAN APPARATUS PoR THE PRODUCTION oF PIPE 8Sheets-Sheet 1 Original Filed June 25, 1949 .flllbf a A TV u INVENTQR.

I A l t 7?/ J. A. HJULIAN 8 Sheets-Sheet 2 Aug. 3, 1954 APPARATUS FORTHE PRODUCTION OF PIPE Original Filed June 25, 1949 Aug. 3, 1954 J. A.HJULIAN APPARATUS FOR THE PRODUCTION OF PIPE 8 Sheets-Sheet 3 OriginalFiled June 25, 1949 INVENTO-R. Mw@ BY a f j Aug. 3, 1954 J. A. HJULIANAPPARATUS FQR THE PRODUCTION oF PIPE 8 Sheets-Sheet 4 Original FiledJune 25, 1949 QQ L@ l NV EN TOR. uw [Lg/MQ@ Aug. 3, 1954 J. A. HJULIANAPPARATUS FOR THE PRODUCTION OF PIPE 8 Sheets-Sheet 5 Original FiledJune 25, 1949 INVENTOR. BLY/mwwyaxwa Aug. 3, 1954 J. A. HJULIAN2,585,115

APPARATUS FOR THE PRODUCTION OF PIPE Original Filed June 25, 1949 8Sheets-Sheet 6 Aug. 3, 1954 .1. A. HJULIAN 2,535,115

APPARATUS FOR THE PRODUCTION OF PIPE Original Filed June 25, 1949 8Sheets-Sheet 7 Aug. 3, 1954 1 A HJUUAN 2,685,115

APPARATUS FOR THE PRODUCTION OF PIPE Original Filed June 25, 1949 8Sheets-Sheet 8 Patented Aug. 3, 1954 UNITED STATE ATEN T OF vF I CEJulius A. Hjulian, Palo Crane Co., Illinois Original application June sChicago,

Heights, Ill., assignor to l., a, corporation of 25, 1949, Serial No.

101,346. Divided and this application September 20, 1950, Serial No.185,744

4 Claims. (Cl. :Z5-16) This invention relates to a new and improvedapparatus for the production of pipe formed from cement and a suitableaggregate. In its preferred form, this aggregate comprises of asbestosfibre.

The apparatus is adapted for the production of pipe by an extrusionprocess under relatively high pressure so that the Ipipe has highdensity and great strength. While the pipe is extruded, means areprovided whereby the extrusion is resisted in such manner that the highpressures may be applied and a large proportion of uncombined water maybe eliminated from the slurry during the process. The apparatus isadapted to lengths of pipe, the possible as far as the method andapparatus are concerned.

It is an object of the present invention to provide a new and improvedapparatus for the production of cement-asbestos pipe or the like.

maybe produced.

It is also an object to provide apparatus by means of which the pipe maybe extruded under high pressures.

It is another object to provide means whereby the extrusion of the pipeis resisted during the application of pressure and whereby the movementof the pipe may be intermittent or substantially continuous.

It is an additional object to provide an apparatus which is automatic inoperation in carrying -out the several steps in the formation andintermittent movement of the extruded pipe.

It is a further object to provide apparatus of this character includingmeans for the elimination of a high percentage of water from the slurryduring the formation of the pipe with the loss Aof Aonly a smallpercentage of the solids in the slurry.

It is also ran object to provide apparatus for the commercial productionof pipe of high quality and adapted for practical use.

Other and further objects will appear as the description proceeds.

This application is a division of my application Serial No. 101,346,filed June 25, 1949.

I have shown certain preferred embodiments vof my invention in theaccompanying drawings, in which- Figure 1 is a somewhat diagrammaticlayout of the apparatus together with the control mechanism;

Figure '2 is a circuit diagram with control switches, relays andYsolenoidsin positions corresponding to the apparatus positions ofFigure 1 Figure 3 is a diagrammatic layout similar to Figure 1 butshowing a further step in the operation;

Figure 4 is a circuit diagram corresponding 'to Figure 3;

Figure 5 is a diagrammatic layout similar .to Figures 1 and 3 butshowing a later step in the process;

Figure -6 is a circuit diagram corresponding to Figure 5;

Figure 7 is a View partly in section and on an enlarged scale showingthe pipe forming 'portion of the apparatus;

Figure 8 is a cross-section taken on line 8 8 or" Figure 7;

Figure 9 is an elevation, on an enlarged scale, of the water-extractioncylinder;

Figure 10 is a section taken on line lll-l0 of Figure 9;

Figure 11 is an enlarged cross-section taken lon line |III of Figure10,'

Figure 12 is a 1 but showing a ing slurry to the slurry cylinder;

Figure 18 is a View similar to Figure 17 showing a construction forfeeding slurry 'direct to the pressure chamber;

Figure 19 is a longitudinal section of amodii-led form of water-removalcylinder;

Figure 20 is a cross-section, on an enlarged scale, taken on line 20-20of Figure 19;

Figure 2l is a fragmentary longitudinal section showing a modified formof construction 4for removal of water the formed material; and

Figure 22 is a cross-section taken on line 22-22 of Figure 2l.

,material Vbeing used,

vproportion of water present .orthe .desired-density of the nal product.This supply pipe 2| is connected through T 22 to the pipe 24 which leadsto the T 25. The opposite side of T 22 leads through relief valve 21 tothe stack 28. This stack 28 is shown with a pressure gauge 29. Theopposite sides of the T 25 lead to the hydraulic valves 3| and 32. Anoutlet pipe 33 controlled by valve 34 leads from hydraulic valve 3| tothe open tank 35. The hydraulic valve 32 has an outlet pipe 31 which isconnected to pressure gauge 30. This pipe 31 terminates in a T 39. Fromthe T 39 the pipe 40 controlled by valve 4| leads to the pressure orwater end 42 of the slurry cylinder 44. The opposite side of T 39 leadsthrough valve 45 to pipe 46. The air supply pipe `41 enters pipe 46, theair supply being operatively controlled by valve 48. A further controlvalve 49 is located in pipe 46 which leads to the slurry hopper 5|.

The slurry hopper is provided, at its lower end, with a check valve 53normally held upward or in its closed position by a spring 54; ttedaround the valve stern 55. One end of the spring 54 bears against themember 51 xedly secured to valve stem 56, while the other end of thespring engages a spider 59 located in the hopper. The valve stem 56 isprovided, at its upper end, with a head 50. As shown in Figure 1, thehopper 5| is shown as closed by cover 52, which engages the valve stemhead 60 to depress the valve stem 58 and open the valve 53. The cover 52is removable.

The lower end of hopper 5| discharges into a T iitting 62, the oppositeopening of which is closed by plug 63. The lateral opening in the T 52is connected by pipe 65 to a cross-iitting 91, the upper opening oiwhich is closed by plug 69. The left lateral side of the crossetting 61is connected by pipe 1| to the slurry end of the cylinder 44. The lowerside of the cross-fitting 61 is connected by pipe 13 to the pressurechamber 15.

The mandrel 11 is fitted in the pressure chamber 15, as best shown inFigure '7, with its left end threaded into the circular flange 18 whichforms a part of the left end closure 19 of the pressure chamber. Thismandrel 11 is hollow and a drain pipe 80 is connected through theclosure member 19. The water-extraction cylinder 82 forms a part of themandrel 11 and beyond this cylinder 82 is a further extension 83 of themandrel. The housing member or die 85 encloses the mandrel, beingthreadedly connected at 86 to the right side of the pressure chamber 15.The brake assembly 81 is located to the right of the housing 85 and isnormally maintained in the left-hand position, in which it is shown inFigure rI, by means of the springs 88 surrounding the rods 89. Theserods 89 extend from the right face of member 85. The springs 88 engageadjustable nuts 90 carried by the rods 89, the adjustment beingmaintained by lock nuts 9 I.

The brake construction is shown in longitudinal section in Figure '1 andin cross-section in Figure 8 and the brake shoes 95 are hydraulicallyoperated in their gripping action and returned to the outer or unclampedposition by means of springs 91. The brake assembly housing 94 housesfour similar brake shoes 95, each of which engages substantially 90 ofthe formed pipe or the slurry support sleeve, as will be described indetail hereafter. Each shoe 95 has studs 96 threaded therein. A spring91 surrounds each stud 96 fitting within a recess 98 in the housing 94and having its upper end bearing against a washer 99 held in adjustedposition by the nuts |00. These studs and springs normally urge theshoes in their retracted positions away from the mandrel. Intermediatethe studs 96, as best shown in the upper right portion of Figure 7,there are provided the pressure plates |02 carrying the cup-shaped seals|04. These seals |04 are held in place by plates |05 and screws |06. Theplates |02 thrust against the shoes by means of balls |01, thuseliminating binding of the parts. These pressure shoes are also shown incrosssection in the lower part of Figure 8, and it will be noted thatthe chambers above the shoes are inter-connected by means of channels|08 formed in housing 94. Cover members |09 are bolted in place to coverthese various chambers and the lowermost cover plate |09 is shown inFigures '7 and 8 as connected to the pipe l0 for the introduction of uidunder pressure.

It will be noted, from an examination of Figure 8, that the inner faces|2 of the brake shoes 95 are shown as serrated so as to have anincreased gripping surface contacting the formed pipe. While thisserration is not essential, it is desirable to have a surface having ahigh coefficient of friction either due to surface treatment or thenature of the material. The outer face of a portion of right-handsection 83 of mandrel 11 is also shown as serrated or knurled as shownat ||3. This, also, is not essential, but it is preferable to have asurface having a relatively high coeilicient of friction. In Figure 7,there is shown extending from a point covering the water drain cylinder82 to a point adjacent the right-hand end of the mandrel 11 a slurrysupport sleeve ||4 which is used only when beginning operation of theapparatus, as will be explained hereafter. This support sleeve ||4 isshown as comprising two end rings ||5 between which is a longitudinallyextending inner tubular member ||6 which is preferably formed from asynthetic resin reinforced with textile fibres and an outer tubularmember ||1 formed of rubber or similar material.

An automatic operating control is provided for the apparatus, thiscontrol operating continuously in a sequence of operations to producethe pipe by a series of intermittent movements of the pipe to the rightover the mandrel 11. This control system comprises the use of air underpressure with the air valves being operated by means of solenoids, whichsolenoids are operated by means of relays. The relays are controlled byswitches actuated by pressures and by the moving parts, as shown inFigure 1.

The hydraulic valves 3| and 32 are operated by means of air underpressure supplied to the valves from the air valve |20 by means of pipesi22 and |23. Pipe |22 is provided with branch |24 leading to the lowside of air cylinder |25 which actuates hydraulic valve 32. This pipe|22 is also provided with a branch |21 leading to the high side of aircylinder |28 controlling hydraulic valve 3|. The pipe |23 is providedwith a branch |30 leading to the high side of air pressure cylinder |25and with a second branch |3| leading to the low side of air cylinder|28. Valve |20 serves to connect the air pressure supply line |33alternately to pipes |22 and |23, ea/ch pipe when not connected to theair supply line |33 being connected to the air exhaust pipe |34. Thisair valve |20 is actuated in the downward direction by mea-ns of thepull of solenoid |36 through lever |31. The return spring |38 serves toreverse the movement of the lever |31 when the solenoid |36 isdre-energized.

The circuit diagram in Figure 2 shows the solenoidA |315 and the relay|39 which serves-to actuatethat solenoid. This relay is controlled byswitch |4I. This switch |4| is shown inFigure asoperated by a lug |42carried by slide rod |43 which is connected to the brake operating lever|45 and reciprocated by the movement of thatH lever. The solenoids |41and |48, shown at the lower right of Figure 1, are also shown in thecircuit diagram of Figure 2. These solenoids |141 and |48 arealternately energized and serve to positively move the rod |49 whichoperates air valve |5|.. This air valve |5| alternately suppliesairunder pressure from air supply line |53 through pipe |54 to the rightend of the air cylinder |55 and similar air under pressure to the leftend of cylinder |55 through the vpipe line |51. Whichever of the pipes|54 and |51 is not connected to the air supply line |53 is connected tothe air exhaust line |58 in the operation of the valve.

The solenoid |41 is put in operation by relay 1.6.0 controlled by aswitch |6| which is adjacent switch |-4| and is operated by lug |62 onthe reciprocating rod |43. Solenoid |48 is controlled by relay |54 whichis put in operation by means of vswitch |55. Switch |55 in the circuitof Figure .2 is the pressure switch shown at approximately the middle ofFigure l and is actuated vby water pressure passing through pipe 51 fromthe water end of the slurry cylinder 44. This switch |66 is a`double-throw switch and the spring |68 normally moves such switch |65against contact |10 when the water pressure is low in the slurrycylinder. This movement of the switch |56, as shown in Figure 2,energizes relay |64, the closing of this relay in turn energizingsolenoid |40 while opening relay |90 and de-energizing solenoid |41 and,consequently, causing a reverse or downward movement of the rod |49 withconsequent reversal of the flow of air through valve |5|.

The circuit diagrams of Figures 2, l and 6 show the line wires |12 and|13 of a usual power supply circuit. The protective fuse leads from line|13 through the main switch |19 to line |11 which leads to one side ofthe switches .controlling relays |39, |90 and |64. The opposite sides ofthese switches |39, |60 and L54 are connected through thesolenoid-operating coils |35, |41 and |49 `into the other side |12 ofthe power line system. A second line |19 leading from the main powerline switch |16 is controlled by a secondary switch |09 to supplycurrent through switches Il, |55 and |4| to the operating coils of therelays |39, |50 and |64. The other sides of these relay coils areconnected by wire |82 to the other line |12 of the power supply circuit.A pilot light |33 is shunted across switch 6| and the actuating coil ofrelay |60 and serves to indicate the operation of switches I 6| and |66.

As shown in Figures 1 and 7, the lever |45 is pivoted at |85 to thehousing 85 and has a shorter lever arm |86 extending above the pivot.This lever arm |85 is connected by a link |88 to the brake housing 94.Consequently, movement of the piston 89 in air cylinder |55 serves, bymeans of the piston rod |9| connected to the lower end of lever |25, toreciprocate the brake housing and the brake parts contained thereinlongitudinally of the mandrel 11. It is to be noted that this movementwhen to the right, in Figures 1 and 7, is opposed by the springs 88which, however, assist in returning the brake assembly to the left uponmovement of the piston |89 to the 6 right. The guide-rods-BS- aresecuredto the vheus-- ing and the brake housing Yassembly 94slidesthereon.

The form of construction shown in Figures 12 to 16 inclusive `provides a-pair of Vbrake assemblies which are used alternately so that` thesubstantially continuous `movement and control of the formed pipeisffacilitated. |The assembly shown in 'Figure 12 does .not include thesupply lines and associa-ted parts for supplying` water under pressureto the lett end of slurry cylinder 44, since these portions of theconstruction are similar to those shown in Figure 1. The'left or waterend of the slurry cylinder itself, the hopper 5|, check valve..53, TV(i2, cross connection 61 and associated parts including thepressurelchamber 15 and fluid drain 30, are also identical with theconstructions shown in Figure 1.

The operating'mechanism comprises a pair of brakes, brake #l being shownat and brake #2 at |92. The operating lever |94 for these brakes ispivoted at |95 to the housing member 85. The link |96 is connected byslotted connection |91 to the upper end of lveer |94 and is pivotallyconnected at |98 to the second brake |92. The slotted connection 200-joins the lever |94Y and lin-k 202 at a vpoint below the pivot |95, thelink 202 being pivoted at 203 to the rst brake |90.

The slide rod y204 is pivotally connected vat 208 a lower portion oflever |94. This slide rod 204 is provided with lug 201 for operatingswitch 208, with lug 2|0 for operating switch 2| l, and with lug 2|3 foroperating switch 2|4. The lower end of lever |94 is connected to apiston rod |-'9| identical with that shown in Figure 1, this rod beingconnected to piston |89 in cylinder |55. This cylinder is operatedt-rough pipes and by means of valve |51 and solenoids |41 and |48 in`the same manner as shown in Figure 1.

The pipe 2|'6 leads from the water end of the slurry cylinder 44 andconnects through pipe 2|1 controlled by valve 2|8 to a drain. Itconnects by pipe 220 to a multiple valve 222, which valve is operated bya piston having the piston rod 224 vextending from air cylinder 225. TheAair valve 22-1 controls the ow of air supplied through pipe 228. Thisair is supplied alternately through pipe 230 to the right -end ofcylinder 225 and through pipe 232 to the left lend ofthe same cylinder.The valve also connects whichever end of the air cylinder is notconnected to the air supply to an air exhaust line 234. The valve 221is. actuated in one direction Aby solenoid 236 and is returned to itsopposite position by spring 231.

The manner in which the gripping action and movement of the two brakesare coordinated is shown in Figures 13 to 16. As shown in Figure 13, therst brake |90 is open and the second brake |92 is in its closed orgripping position. The brakes are located adjacent each other. In Figure14, the rst brake has begun its moveing with it the slurry supportsleeve or the pipe, upon the period of operation. As shown in Figure.15, the second brake I 92 has completed its movement to the right andthe shoes have been withdrawn to the open position. At this time, therst brake |90 has closed and is now gripping 'the pipe or slurry supportsleeve. In Figure 16, the rst brake |90 is still in the closed positionand is moving to the right towards the second brake |92. This secondbrake is still open and is moving to the left towards the first brake.The next position in the cycle is shown in Figure 13 where the twobrakes have reached positions closely adjacent each other and the firstbrake has released while the second brake |82 has gripped.

Figures 17 and 18 show alternate forms of oonstruction which provide forthe introduction of the slurry into the system at points differing fromthe introduction as shown in Figures 1, 3 5 and 12. In Figure 11, theslurry feed hopper 360 feeds directly into the slurry end of the slurrycylinder 36|. This cylinder is similar to those shown in Figures 1, 3, 5and 12 and is provided with a floating piston 362, pipe 383 for theintroduction of water under pressure, and pipe 384 for the relief of thepressure and for the drainage of water from the cylinder. The hopper 308is similar in construction to that shown in the other figures, beingprovided with the check valve 365 normally held closed by spring 366.This valve is opened in the manner previously described by pressing downon the knob 361 on the valve rod 368, this pressure being applied byfitting a cover tightly on the hopper when the slurry is to beintroduced. The slurry cylinder 36| is shown as feeding the slurry underpressure into the pressure chamber 318 through the pipe connections 312.The particular construction of the means for dewatering the slurry andwithdrawing the water and air may take the form of any one of thevarious constructions illustrated in the other figures.

In Figure 18, the slurry hopper 388, with its valve 382, feeds directlyinto the pressure chaml ber 383. The mandrel 385 is shown as supportedon vanes 386, the circumference of the mandrel being reduced at thepoint where it extends opposite the valve 382. The pipe 388 forwithdrawing water and air from the mandrel extends through one of thevanes 386 to the outside of the pressure chamber. It will be understoodthat the vanes 386 are widely spaced to offer a minimum of obstructionto the slurry while supporting the mandrel 385.

One form of the water-removing cylinder is shown in detail in Figures 9.to 11 inclusive. This cylinder comprises a central member 240 which hasa central cylindrical opening 24|. Member 248 has a reduced threadedportion 243 at the left end and a shorter threaded portion 244 at theright end. The right end is provided with the integral cylindricalshoulder 246. The plurality of rings 248 are assembled on the supportingmember 240 against the shoulder 246 and held in position by the lockingring 250 which is threaded onto the left end of the member 248. Thislocking ring 258 is shown as provided with the recesses 25| for theapplication of a suitable wrench to be used in tightening up theassembly. As shown in Figure 11, the member 240 is provided with aplurality of longitudinally extending slots 252 which lead from theunder face of the rings 248 to the central passage 24|. The member 240is provided with a longitudinally extending rib 254 which fits intonotches 255 formed in the several rings 248. Each ring 248 is providedon one face with a plurality of lands or raised places 251 alternatingwith smaller raised places 258 which separate the major portion of theadjacent faces of the rings. These rings are all placed on member 248with the lands all facing in the same direction so that the lands spacethe rings 248 apart to provide narrow slits for the passage of water. Asshown in Figure l0,

the inner edges of the rings are chamfered at 260 to provide for freemovement of the water to the passage 24|.

Another form of water-removing cylinder has been shown in Figures 19 and20. This cylinder comprises a body member 30| having threaded ends 382and 383. The intermediate portion of the cylinder is longitudinallyslotted, as shown at 305 and 306, with a central unslottedcircumferentially extending ring 381. The member between adjacent slots305 and 306 has its circumferential surface cut away, as shown at 388and 303, to provide clearance below the longitudinally extending bars3||. These bars 3|| have lugs 3|2 and 3|3 at their ends. The lugs 3|2intert in a corresponding groove in a flange 3 5 extending from the endof the body member 38| adjacent the threaded portion 383. A locking ring3|1 is threaded onto the threaded end 302, the lugs 3|3 fitting into acorresponding circumferentially extending groove as shown. Spacedopenings 3|8 are provided in ring 3|1 for the use of a wrench fortightening the ring into position. As shown at 328, each of the bars 3||has, on one side, a plurality of narrow upwardly extending surfaces orlands 320. These serve to space apart the major portion of the adjacentfaces of the bars 3|| and provide longitudinally extending slots for thepassage of water and air for dewatering the slurry. It will beunderstood that the threaded portions 302 and 303 serve to join thedewatering cylinder to adjacent portions of the mandrel.

A further form of construction for dewatering the slurry is shown inFigures 2l and 22. These figures show a solid mandrel 338 extending froma pressure chamber 332 into a tubular mold 333. The mold 333 is threadedat 335 onto the projection 335 of the pressure chamber, a gasket 331being provided to effect a fluid-tight joint. A plurality of rings 348are supported in a circumferentially extending recess in the member 333,these rings being spaced apart by lands 342 so as to provide interruptedcircumferentially extending slits to permit the passage of water and airoutwardly from the mold chamber 344. The outer edges of the rings 340are chamfered, as shown at 343, to facilitate the passage of the fluids.As shown in Figure 22, these rings 348 are provided with notchescorresponding to a locking bar 341 which also fits in a longitudinalslot in the member 333. This permits positive location of the rings andprevents their rotation. Water withdrawal chambers 348 are located atcircumferentially spaced points around the rings 348, these chambers 349being connected by passages 35| to the circumferentially extendingcollecting chamber 353. This chamber is provided with the outlet passage355 by which the water and air may be drained ol by gravity or drawn offby suction, as desired. It will be noted, from Figure 21, that thechamber 353 has its outer wall formed by a separate ring member 356which is threaded onto the member 333 at 358, a gasket 359 beingprovided at the other end to secure a fluid-tight joint.

In the operation of the apparatus shown in Figures 1 to 6 inclusive forthe production of pipe, a slurry or mixture of cement, asbestos andwater is introduced into the system and reaches the ring-like spacebetween the die or housing and the mandrel 11. While differentproportions of materials may be used, I have found that three parts ofcement to one part of asbestos fibres with sufficient water to provide afluid slurry has proven satisfactory. Pressure is applied behind theslurry, this pressure being resisted in the initial operation of themachine by the slurry support sleeve I4 which is held by the brake 94.After the process has proceeded and a length of pipe suihoiently long toextend beyond the mandrel has been produced, the slurry support sleeveis no longer used. Under these conditions, the pipe previously formedacts as a slurry support, being held by the brake 94 against the mandrel11. Upon the slurry being compressed by the pressure applied behind it,the surplus water in the slurry is extracted through the small openingsin the water-extraction cylinder` 32 and is drained or drawn off bysuction through the left end of the mandrel and through pipe fitting 80,shown in Figure '1. When the predetermined pressure behind the slurry isreached, the brake mechanism with the brake jaws closed moves to theright, carrlng with it the extruded pipe or the slurry support sleeve.When the pressure is released behind the slurry, the brake jaws open andthe brake mechanism moves to the left back to its starting positionwhile the formed pipe or slurry support sleeve remain in their righthandposition to which they have been moved under the gripping hold of thebrake. The slurry is again compressed as the brake jaws close and theoperation is repeated,

The specific method of carrying out the process briefly described aboveis indicated in the several gures of the drawing. Referring first toFigure l, the slurry support sleeve H4 is inserted into the open end ofthe extruding chambers, being slipped over the mandrel and slid in untilits left end covers the major portion of the water-removing cylinder 82,as shown in Figure 7. The slurry which has been previously mixed ispoured into the hopper 5|. It is necessary, at this time, to close thehopper and a removable cover 52 is secured to the top of the hopper,engaging the end 69 of the valve stem 55 and iorcing the valve 53downwardly to open position. Valve 45 is closed and valves 48 and 49 areopen so that compressed air is supplied to the top of the hopper 5I.This forces the slurry out of the hopper and through pipe 55 to thefitting 51 where a portion of it passes into the slurry cylinder 44.Another portion passes downwardly through pipe 13 to the chamber 15about the left end of the mandrel 11. The slurry forces the floatingpiston 43 to the left in the slurry cylinder 44 to substantially theposition in which it is shown in Figure l. After the slurry has beenforced out of the hopper 5| by this compressed air, the air is shut oiTby closing valves 48 and 49 and the cover 52 removed from the hopper.The spring 54 automatically returns the check valve 53 to closedposition.

To start the apparatus into operation, the main switch |15 and secondarycontrol switch |89 are closed manually. At this point in the operation,switches |4| and |5| are in the closed position, having been left inthat position by the nal movement of the lower end of the lever |45 tothe right in the previous operation. Switch I 4I being closed, operatesrelay |33 to close solenoid I 35 which moves the air valve to theposition in which it is shown in Figure l, the valve then serving toopen the hydraulic valve 32 and close hydraulic Valve 3|. The waterunder high pressure from the ram passes through valve 32 and throughT-tting 3S and pipe 40 to the water or left end of the slurry cylinder44 behind the floating piston 43. It will be understood that themanually-operated valve 4| is opened while the upper valve 45 is .closedbefore beginning this operation.

Water pressure thus starts to build up in the water end of the slurrycylinder 44. While this pressure is being built up, surplus water fromthe ram exhausts through valve 3| to the open tank 35. At the time ofbeginning the process, since there is no initial pressure in the waterchamber behind the piston 43, the pressure switch |66 is closed againstcontact |10 so that relay |64 isoperated to energize solenoid |48.Solenoid |48 holds the air valve |5| in such position that it providesair under pressure through line |51 and holds the piston llle'to theright and, through the piston rod |9|, lever |45 and link |88, holds thebrake assembly ed at its left limit of movement.

As the slurry is compressed, some of the water is extracted from theslurry being forced by the pressure through the slits provided betweenthe water-extraction rings 2:38 on the water extraction cylinder 82which is part of the mandrel. This water passes out through pipe to adrain. This may be a gravity drain or suction may be applied tofacilitate the removal of the water. When a predetermined pressure,which may be on the order of 1,9()0 pounds per square inch, has beenreached on the water side of the floating piston '4.3 in the slurrycylinder 44, this pressure serves to operate the pressure switch |66 andto swing it to the left in the position in which it is shown in Figure4. This de-energizes relay |65 and solenoid |48 and energizes relay |60and solenoid ifi?. It will be understood that, at this time, switch |6|remains closed.

Solenoid |41 pulls the rod |49 upwardly to the position in which it isshownv in Figure 3. This serves to reverse the liow of air through valve5| and air behind piston |89 in cylinder |55 is exhausted while airunder pressure is introduced in front of the piston. This moves thepiston to the left, as shown in Figure 3. The lever |45, being pivotedat |85 and the upper end of lever |45 being connected by link |88 to thebrake assembly |94, this left movement of piston |89 moves the brakeassembly to the'right. As the lower portion of the lever |45 moves tothe left it pushes the switch-actuating rod |43 to the left and switch|4| is opened by lug |42. This switch |4| then opens the circuit torelay |39, deenergizing solenoid |35. The spring |38 reverses theposition of valve |26 upon the inactivation of solenoid |36. Thisreverses the air supply to the two hydraulic valves 3| and 32. Valve 32closes to the water supply and exhausts its connection |26 to the waterside of the floating piston 43 and slurry cylinder 44 to the open tank35, thus reducing the pressure 4in the water end of the slurry cylinder.Valve e I, also being opened, discharges to the open tank. These actionsoccur as the brake is moving to the right, moving with it the slurrysupport cylinder or the formed pipe. It will be understood that if theslurry support cylinder is being moved, the formed pipe will followclosely behind the left end of that cylinder ydue to the pressure in thechamber about the mandrel.

As the brake assembly reaches its limit of movement to the right, asshown in Figure 5, the piston |89 in air cylinder |55 has completed itsmovement to the left. The completion of this movement serves to bringlug |62 in contact with the switch-operating mechanism of switch |6| andopens that switch. At substantially the same time that switch ll isopened, pressure switch |55 is relieved of its pressure and swings theswitch |66, shown in Figures 2, 4 and 6, back to the right-hand positionas shown in Figures 2 and 6. This movement of the switch |66 serves tode-energize the relay ISU and thus cle-energizes the solenoid |41. Thissolenoid |41 thus releases rod |49, which has operated the air valve|5I. This movement'l of switch |66 serves to energize relay |64 whichenergizes solenoid |48 to pull the rod |49 downwardly.

When the pressure is reduced in the water end of the slurry cylinder, itis also reduced through pipe line ||0 which leads to the pressurechambers in the brake assembly and the brake shoes are released or drawnaway from the formed pipe or slurry support cylinder by means of theseveral springs 91, as shown in Figure 8. At the same time, as statedabove, pressure switch |66 engages contact operating relay |64 operatingsolenoid |48 which operates air valve |5| to supply air in the left endof air cylinder |55 to return the open brake assembly to the left. Asthe brake mechanism moves to the left, the lugs |42 and |62 close firstswitch 16| and then switch |4| which closes relay |39 energizingsolenoid |36 which, through air valve |20, again applies the waterpressure through valve 32 to the water end of the slurry cylinder 44.Switch |6| closes the secondary circuit to relay |60 so that the circuitis ready to be operated by the movement of pressure switch |66 when thepressure reaches the predetermined amount. This pressure builds up inthe slurry cylinder back of the slurry piston 43 and the cycle beingcompleted, the above described steps continue in the order described.

As the operation continues automatically, the slurry support sleevegradually works out from between the mandrel and the die and normalextrusion of the pipe takes place. As the pipe extrudes from theapparatus it is preferably supported in a trough since, while it is veryhard and dense, it has not cured and should be supported until thecement has set and the pipe is fully cured. The slurry cylinder may berefilled with slurry from time to time in the manner de scribed wheneverthe slurry has become used up in the operation. It will be understoodthat the slurry cylinder may be made of such a size as to produce a verysubstantial length of pipe without refilling. Once the process hasstarted it may be continued indefinitely without again using the slurrysupport sleeve. entirely continuous and may be cut in any suitablelengths as desired for use.

When the slurry is mixed, there will be a certain amount of airentrained with the slurry in the mixing operation. This entrained airhas proven to be a desirable factor in the carrying out of the process.The other constituents of the slurry, the water, cement and asbestos,are substantially non-compressible. The air, however, is of coursehighly compressible, thereby serving as a cushion, and this assists inthe smooth movement of the floating piston 43 in the operation offorming the pipe. Due to the high pressures used, the entrained air isforced out of the slurry with the major portion of the water and passesthrough the narrow slits between rings 248 of the water-extractioncylinder, the air thereby having a cleansing effect in keep ing theslits open. This cylinder has been made with slits having a Width offrom five to ten one-thousandths of an inch and, in this range, hasproven highly effective. The water and air pass out of the slurrythrough the slits, the water carrying with it in suspension only a verysmall 75 The pipe, as extruded, is

portion of the more finely divided cement. This leaves only an extremelydense mixture of cement and asbestos fibres, together with a smallamount of water to pass by the Water-extraction cylinder 82. The processand apparatus, therefore, form a hard, dense pipe which, when fullycured, has high tensile and compressive strength. The pipe is also notas brittle or subject to fracture by careless handling, as is castcement pipe made under atmospheric pressure.

While I have shown certain preferred embodiments of my invention, theyare to be understood to be illustrative only as it is capable ofvariation to meet differing conditions and requirements, and Icontemplate such modifications as come within the spirit and scope ofthe appended claims.

I claim:

l. Apparatus for producing continuous compacted composition shapes byextrusion molding which comprises a chamber for holding the composition,means for applying pressure to the composition in said chamber, anopen-ended die, a passage connecting the composition chamber and thedie, means associated with the die for withdrawing fluid from thecomposition in the die, brake members for selectively gripping andreleasing the composition in the die and positively operating means forreciprocating the brake members along the line of movement of thecomposition in the die.

2. Apparatus for producing continuous compacted composition shapes byextrusion molding which comprises a chamber for holding the composition,hydraulic means for applying pressure to the composition in the chamber,an openended die, a passage connecting the composition chamber and thedie, brake members adapted for gripping formed composition adjacent theopen end of the die, hydraulic means for moving the brake members togripping position, means for intermittently applying hydraulic pressureto the means in the composition chamber for applying pressure to thecomposition, valve means for controlling said intermittent applicationof pressure, a control for said valve means actuated by the pressureapplied to release pressure upon said pressure reaching a predeterminedupper limit and to reapply pressure upon its reaching a predeterminedlower limit, and means conducting hydraulic pressure from the means forapplying pressure to the composition in the chamber to the brakeactuating hydraulic means whereby the brakes are moved to grippingposition substantially simultaneously with application of pressure tothe composition.

3. Apparatus for producing continuous compacted composition shapes byextrusion molding which comprises a chamber for holding the composition,hydraulic means for applying pressure to the composition in the chamber,an openended die, a passage connecting the composition chamber and thedie, brake members adapted for gripping formed composition adjacent thcopen end of the die, means for moving the brake members to grippingposition, means for restoring the brake members to release position,valves for controlling the hydraulic pressure to the composition,positively operating means for moving the brake means axially of thedie, and interlocking control means whereby the brakes are moved togripping position when pressure is applied to the composition.

4. Apparatus for producing continuous compacted composition shapes byextrusion molding position, hydraulic means for applying pressure to theComposition in the chamber, an openended die, a passage connecting thecomposition ehamber and the die, brake members adapted for grippingformed Composition adjacent the open end of the die, means for movingthe brake members to gripping position, means for restoring 1he brakemembers to release position, valves for Controlling the hydraulicpressure to the composition, positively operating means for moving thebrake means axially of the die, and interlocking Control means wherebythe brakes are moved to gripping position and move-d axially of the dietoward the open end of the die when pressure is appliedL to thecomposition.

References Cited in the file 0I" this patent Number Number UNITED STATESPATENTS Name Date Brown Nov. 13, 1917 Humphrey May 18, 1926 Grupe Oet.30, 1928 Cummins et al Oct. 7, 1947 FOREIGN PATENTS Country Date GreatBritain Nov. 16, 1933

